The continual retirement of existing electrical power transformers poses a substantial disposal problem because of toxic materials contained therein, especially PCBs. Because of the presence of the toxic materials, the recycling of otherwise useful materials (especially copper and other conductive metal) contained therein is discouraged due to health, environmental and safety reasons.
Conventional methods of salvaging conductive material from electrical power transformers are generally very labor-intensive, expensive, and relatively unsafe. Presently, most reclaiming operations use either wire stripping or thermal-wire reclaimers to salvage the valuable conductive materials from the cores of discarded transformers. A wire stripping process, besides being labor-intensive, is very slow and is generally conducted in an environment with an elevated temperature and hazardous environmental atmosphere, which requires a worker to wear a tyvek suit, a respirator and other protective gear. In addition, reclamation by stripping usually results in low recovery efficiency. Also, as the process is boring, workers frequently lose concentration leading to accidents and injury.
A thermal-wire reclamation process utilizes temperatures which are sufficient to pyrolyse or "vaporize" the paper insulation from the surfaces of the conducting material. Unfortunately, the temperatures used for thermal reclamation are generally sufficient to cause deterioration in the quality of the metallic material. More importantly, the residual ash which remains after such paper pyrolysis can contain measurable quantities of hazardous chemicals, including PCDDs and PCDFs. When such ash is subsequently dislodged, a worker is potentially exposed to dioxins and dibenzo furans. In addition, stack effluent from furnaces associated with the thermal reclamation contains such undesirable compounds that are consequently spread throughout the surrounding environment. In addition, thermal reclamation processes generally produce a substantial environmental odor that can create a public nuisance.